After losing the dog statue he had struggled so hard to obtain, Papa has once again turned into a dog. With Bong-gu absent, Hyang-gi finds it difficult to take care of Cheonhajangsa on her own, so she asks her younger sister, Seol-gi, for help. Hyang-gi announces that Seol-gi will be staying with them until Bong-gu returns from his overseas business trip. However, Papa and Byeol-i, who know all too well how volatile Seol-gi’s moods can be, are less than thrilled about her arrival. Determined to turn back into a human as soon as possible, Papa vows to do whatever it takes. Meanwhile, an unfamiliar family moves into Byeol-i’s apartment building: Kang Cheon, who seems friendly, his son Kang Baek, and Mansour, an elderly dog whose mind has become increasingly muddled with age. As it turns out, Mansour, just like Bong-gu, lost his dog statue and was transformed into a dog. With a plan to steal Bong-gu’s dog statue, Kang Cheon approaches Papa and Byeol-i...